Corrosion inhibited lubricants



United States Patent Oflice 3,185,646 Patented May 25, 1965 3,185,646 CORROSION INHIBITED LUBRICANTS Robert G. Anderson, Novato, and Yngve G. Hendrickson,

El Cerrito, Calif., assignors to California Research Corporation, San Francisco, Calif., a corporation of Delaware No Drawing. Filed Sept. 28, 1962, Ser. No. 227,052

5 Claims. (Cl. 252-46.7)

This invention pertains to lubricating oil compositions having incorporated therein metal-free detergents. These particular detergents are also effective as corrosion inhibitors.

Present day internal combustion engines operate at high speeds and high compression ratios. When used in the so-called City stopand-go driving, which includes the greater part of the driving conditions for a large percentage of todays automobiles, the internal combustion engines do not reach the most efficient operating tem perature. Under City driving conditions, large amounts of partial oxidation products are formed, and reach the crankcase of the engine by blowing past the piston rings. This phenomenon is noticed more in engines having greater wear during the break-in period. Most of the partial oxidation products are oil-insoluble, tending to form deposits on the various operating parts of the engine, such as the pistons, piston rings, etc. For the purpose of preventing the deposition of these products on the various engine parts, and to reduce break-in wear, it is necessary to incorporate detergents and wear-reducing agents in the lubricating oil compositions, thus keeping these polymeric products dispersed in a condition unfavorable for deposition on metals.

A great number of the detergents which are added to crankcase oils to reduce this formation of sludges and varnishes are metal organic compounds, particularly those compounds wherein the metal is linked to an organic group through an oxygen atom. Although these metal-containing organic compounds have some effectiveness as detergents for dispersing the precursors of the deposits within the oil itself rather than permitting them to form as deposits on the engine parts, they have the disadvantage of forming ash deposits in the engine. These ash deposits lower engine performance by fouling spark plugs and valves, and contributing to pre-ignition.

It is a particular object of this invention to provide lubricating oil compositions having incorporated therein metal-free detergents which are also effective as corrosion inhibitors. Thus, these new additives disperse the undesirable polymeric products which are formed, and also inhibit corrosion to metal wearing surfaces.

Therefore, in accordance with this invention, it has been found that lubricating oil compositions particularly useful for heavy duty service are obtained by incorporating therein a product obtained by (1) reacting an alkenyl succinic anhydride with phosphorus pentasulfide followed by (2) reacting the product of (l) with a polyalkylene polyamine.

By the use of lubricating oil compositions containing the reaction products described herein, diesel and gasoline engine parts remain remarkably free of deposits and varnish, even under severe operating conditions. In addition these lubricating oils reduce break-in-wear.

The alkenyl succinic anhydride reactants are of the formula R-CH-C wherein R is a hydrocarbon radical having from 30 to 200 carbon atoms therein, preferably from to 200 carbon atoms.

Examples of alkenyl radicals include propylene polymers containing from 30 to 200 carbon atoms, and polymers of mixtures of l-butene and isobutene having from 30 to 200 carbon atoms.

The polyalkylene polyamines, which contribute the imide nitrogen and the basic nitrogen atoms of the reaction products herein, are derived from polymers of ethylene or propylene, such as polyethylene polyamine, and polypropylene polyamines. Such polyalkylene polyamines may be represented by the formula wherein the R represents the divalent radical ethylene or propylene, and x is a number having a value from 1 to 10 or more. Examples of these polyalkylene polyamines include diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine. dipropylene triamine, dipropylene tetramine, tetrapropylene pentamine, pentapropylene hexamine, di-trimethylene) triamine, tri(trimethylene), tetramine, tetra-(trimethylne) petamine and pen-ta-(trimethylene hexamine.

Other polyalkylene polyamines can be exemplified by the aminoalkyl piperazines, for example, ,8 aminoethyl piperazine.

The mol ratio of phosphorus pentasulfide to succinic anhydride can vary from 5:1 to .5 :1; preferably, 1.5 :l to 3:1.

With regard to the polyalkylene polyamine, the mol ratio of polyalkylene polyamine to anhydride can range from 0.5:1 to 1:1, preferably 0.8 to 1.

In the reaction herein between the anhydride and the P 8 the reaction temperature can vary from 100 F. to 450 F., preferably from 250 F. to 350 F.

In the reaction between the P 8 anhydride product and polyamine, the reaction temperature is from 250 F. to about 450 F., preferably 280 F. to 350 F.

Lubricatin oils which can be used as base oils to form lubricating oil compositions of the above-described additives include a wide vairety of lubricating oils, such as naphthenic base, paraflin base, and mixed base lubricating oils, other hydrocarbon lubricants, e.g., lubricating oils derived from coal products, and synthetic oils, e.g., alkylene polymers (such as polymers of propylene, butylene,

etc., and the mitxures thereof), alkylene oxide-type polymers (e.g., propylene oxide polymers) and derivatives, including alkylene oxide polymers prepared by polymerizing the alkylene oxide in the presence of water or alcohols, e.g., ethyl alcohol, dicarboxylic acid esters (such as those which are prepared by esterifying such dicarboxylic acids as adipic acid, azelaic acid, suberic acid, sebacic acid, alkenyl succinic acid, fumaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, 2- ethyl hexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids of phosphorus, alkyl benzenes, (e.g., monoalkyl benzene such as dodecyl benzene, tetradecyl benzene, etc.),

and dialkyl benzenes (e.g., n-nonyl 2-ethyl hexyl benreaction product useful herein as corrosion inhibitors anddetergents.

EXAMPLE I A mixture of 94 grams of phosphorus pentasulfide, 500 grams of polyisobutenyl succinic anhydride, wherein the polyisobutenyl radical contained approximately 66 carbon atoms, and 500 grams of xylene was heated at reflux temperatures for a period of 12 hours. The xylene was distilled off under reduced pressure. For convenience the product is called Product A.

250 grams of Product A cooled to 200 F. was added dropwise to a flask containing 16.6 grams of tetraethylene pentamine heated to 200 F. The reaction mixture was blanketed with nitrogen. After all of Product A had been added, the mixture was heated to 310 F. The reaction mixture was heated at this temperature for 0.25 hour at an absolute pressure of about 200 mm. Hg followed by 0.75 hour at an absolute pressure of 5 mm. Hg.

The remaining reaction product contained:

Weight percent Phosphorus 3.21 Sulfur 5.94 Nitrogen 3 Table I hereinbelow presents further data on the effectiveness of the reaction products described herein as lubrication oil additives, The data of Table I were obtained after 60 hours of operating under the severe conditions of a Caterpillar 1-H engine test used to qualify oils under the 2104 B procedure. This Military specification procedure is so severe that the engine will not even operate with a base oil uncompounded. Even a base oil with the normal commercial additives under this procedure does not proivde sufficient lubrication; that is, the engine itself eventually sticks.

The base oil used in obtaining data for Table I consisted of a California parafiinic base oil having a viscosity of 500 SSU at 100 F., and having incorporated therein 15 mM./kg. (i.e., 15 millimols of metal per kilogram of the finished lubricating oil composition) of a basic sulfurized calcium phenate, and 12 mM./kg. of a zinc dialkyl dithiophosphate.

The PD Nos. refer to the piston discoloration rating. After the engine test, the three piston lands are examined visually. To a piston land which is completely black is assigned a PD N0. of 800; to one which is completely clean, a PD No. 0; to those intermediate between those completely black and completely clean are assigned PD Nos. intermediate in proportion to the extent and degree of darkening.

The GD Nos. refer to the percentage deposit in the piston ring grooves; that is, a 0 evaluation being a clean groove, and a evaluation being a groove full of deposits.

The mol ratio of the phosphorus pentasulfide to the anhydride was 2: 1.

1. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity and from 0.1% to 40%, by weight, of a product obtained by reacting (1) an alkenyl succinic anhydride having from 30 to 200 carbon atoms in the alkenyl radical with phosphorus pentasulfide at temperatures in the range of 100 F. to 450 F. wherein the phosphorus pentasulfide-anhydride mol ratio is from 5:1 to 0.5 :1 followed by (2) reacting the product of (1) with a polyalkylene polyamine at temperatures from 250 F. to 450 F. wherein the mol ratio of said polyamine to said anhydride is from 0.5:1 to 1:1, said polyalkylene polyamine being of the formula wherein R is selected from the group consisting of ethylene and propylene and x is a number from 1 to 10.

2. The lubricating oil composition of claim 1 wherein said product is present in amounts from 0.1 to 15% by weight.

3. The lubricating oil composition of claim 2 wherein said phosphorus pentasulfide-anhydride mole ratio is from 3:1 to 1.5 l.

4. The lubricating oil composition of claim 3 wherein said phosphorus pentasulfide-anhydride is reacted with said polyalkylene polyamine at temperatures from 280 F. to 350 F. Y

5. The lubricating oil composition of claim 4 wherein said polyalkylene polyamine is tetraethylene pentamine.

References Cited by the Examiner UNITED STATES PATENTS 2,733,235 1/56 Cross et a1. 25232.7 2,773,862 12/56 Musselman 25232.7 3,018,247 1/62 Anderson et a1. 25232.7

DANIEL E. WYMAN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,185,646 May 25, 1965 Robert G. Anderson et a1.

It is hereby certified that error appears in the above numbered patent reqliring correction and that the said Letters Patent should read as correctedbelow.

Column 2, lines 23 and 24, for "di-trimethylene)" read di(tri'methylene) line 2.4, after "tri(trimethylene)" strike out the comma; lines 24 and 25, for "tetra- (trimethylne) petamine and penta- (trimethylene hexamine" read tetra- (trimethylene) pen'tamine and penta-(trimethylene) hexamine line 41, for "Lubricatin" read Lubricating line 43, for "vairety" read variety same column 2, line 62, for "esters" read ethers column 3, line 13, for "200 P," read 200 F, lines 26 and 27, for "lubrication" read lubricating same column 3, line 34, for "proivde" read provide Signed and sealed this 26th day of October 1965,

(SEAL) Aiiest:

ERNEST w. SWIDER EDWARD J. BRENNER Ailcsting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,185,646 May 25, 1965 Robert G. Anderson et al.

It is hereby certified that error appears in the above numbered patent reqiiring correction and that the said Letters Patent should read as corrected below Column 2, lines 23 and 24, for "di-trimethylene)" read di (trimethylene) line 2 4, after "tri (trimethy1ene)" strike out the comma; lines 24 and 25, for "tetra-(trimethylne) petamin and penta- (trimethylene hexamine" read tetra- [trimethylene] pen'tamine and penta-(trimethylene) hexamine line 41, for "Lubricatin" read Lubricating line 43, for "vairety" read variety same column 2, line 62, for "esters" read ethers column 3, line 13, for "200 P." read 200 F. lines 26 and 27, for "lubrication" read lubricating same column 3, line 34, for "proivde" read provide Signed and sealed this 26th day of October 1965.

(SEAL) Altest:

ERNEST W. SWIDER EDWARD J BRENNER Allcsting Officer Commissioner of Patents 

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY AND FROM 0.1% TO 40%, BY WEIGHT, OF A PRODUCT OBTAINED BY REACTING (1) AN ALKENYL SUCCINIC ANHYDRIDE HAVING FROM 30 TO 200 CARBON ATOMS IN THE ALKENYL RADICAL WITH PHOSPHORUS PENTASULFIDE AT TEMPERATURES IN THE RANGE OF 100*F. TO 450*F. WHEREIN THE PHOSPHORUS PENTASULFIDE-ANHYDRIDE MOL RATIO IS FROM 5:1 TO 0.5:1 FOLLOWED BY (2) REACTING THE PRODUCT OF (1) WITH A POLYALKYLENE POLYAMINE AT TEMPERATURES FROM 250*F. TO 450*F. WHEREIN THE MOL RATIO OF SAID POLYAMINE TO SAID ANHYDRIDE IS FROM 0.5:1 TO 1:1, SAID POLYALKYLENE POLYAMINE BEING OF THE FORMULA 